<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<u>u标签</u>
		<i>i标签1</i>
		<a href="">a标签</a>
		<a style="display: block;">变成块元素的a标签独占一行</a>
		<div class="box">
			文本垂直方向居中
		</div>
		
		<div>
		
		    <span data-tooltip="hello world">Hover Me!!!</span>
		
		</div>
		
		<style type="text/css">
			.box{
				border: 1px solid black;
				height: 30px;
				line-height: 30px;
				width: 300px;
			}
			
			
		</style>
	</body>
</html>
